Less fatal errors

dart/pkg/compiler/lib/src/resolution/members.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of resolution;
 
 abstract class TreeElements {
   AnalyzableElement get analyzedElement;
   Iterable<Node> get superUses;
 
@@ skipping 2227 matching lines @@
 
   ResolutionResult visitIdentifier(Identifier node) {
     if (node.isThis()) {
       if (!inInstanceContext) {
         error(node, MessageKind.NO_INSTANCE_AVAILABLE, {'name': node});
       }
       return null;
     } else if (node.isSuper()) {
       if (!inInstanceContext) {
         error(node, MessageKind.NO_SUPER_IN_STATIC);
-        // TODO(ahe): Don't throw, recover from error.
-        throw new CompilerCancelledException(null);
       }
       if ((ElementCategory.SUPER & allowedCategory) == 0) {
         error(node, MessageKind.INVALID_USE_OF_SUPER);
       }
       return null;
     } else {
       String name = node.source;
       Element element = lookupInScope(compiler, node, scope, name);
       if (Elements.isUnresolved(element) && name == 'dynamic') {
         // TODO(johnniwinther): Remove this hack when we can return more complex
         // objects than [Element] from this method.
         element = compiler.typeClass;
         // Set the type to be `dynamic` to mark that this is a type literal.
         registry.setType(node, const DynamicType());
       }
       element = reportLookupErrorIfAny(element, node, node.source);
       if (element == null) {
         if (!inInstanceContext) {
           element = warnAndCreateErroneousElement(
               node, node.source, MessageKind.CANNOT_RESOLVE,
               {'name': node});
           registry.registerThrowNoSuchMethod();
         }
       } else if (element.isErroneous) {
         // Use the erroneous element.
       } else {
         if ((element.kind.category & allowedCategory) == 0) {
-          // TODO(ahe): Improve error message. Need UX input.
-          error(node, MessageKind.GENERIC,
-                {'text': "is not an expression $element"});
-        // TODO(ahe): Don't throw, recover from error.
-          throw new CompilerCancelledException(null);
+          element = warnAndCreateErroneousElement(

[Johnni Winther, 2015/01/09 08:44:17]

Add a TODO to create a more precise erroneous element kind.

[ahe, 2015/01/09 10:43:46]

Are you suggesting that we decode allowedCategory and create a matching element?

[Johnni Winther, 2015/01/09 11:12:47]

Yes.

[ahe, 2015/01/09 11:43:24]

Done in CL 837563004.

+              node, name,
+              MessageKind.GENERIC,
+              // TODO(ahe): Improve error message. Need UX input.
+              {'text': "is not an expression $element"});
         }
       }
       if (!Elements.isUnresolved(element) && element.isClass) {
         ClassElement classElement = element;
         classElement.ensureResolved(compiler);
       }
       return new ElementResult(registry.useElement(node, element));
     }
   }
 
@@ skipping 2625 matching lines @@
     // TODO(johnniwinther): Change errors to warnings, cf. 11.11.1.
     if (element == null) {
       return failOrReturnErroneousElement(resolver.enclosingElement, node, name,
                                           MessageKind.CANNOT_RESOLVE,
                                           {'name': name});
     } else if (element.isErroneous) {
       return element;
     } else if (element.isTypedef) {
       error(node, MessageKind.CANNOT_INSTANTIATE_TYPEDEF,
             {'typedefName': name});
+      element = new ErroneousElementX(

[Johnni Winther, 2015/01/09 08:44:18]

Ditto.

[ahe, 2015/01/09 10:43:46]

Are you thinking of an element like this:

class ErroneousConstructorX extends ErroneousElementX {
...
}

[Johnni Winther, 2015/01/09 11:12:47]

Yes.

[ahe, 2015/01/09 11:43:24]

Done in CL 837563004.

+          MessageKind.CANNOT_INSTANTIATE_TYPEDEF,
+          {'typedefName': name}, name, resolver.enclosingElement);
     } else if (element.isTypeVariable) {
       error(node, MessageKind.CANNOT_INSTANTIATE_TYPE_VARIABLE,
             {'typeVariableName': name});
-      // TODO(ahe): Don't throw, recover from error.
-      throw new CompilerCancelledException(null);
+      element = new ErroneousElementX(

[Johnni Winther, 2015/01/09 08:44:18]

Ditto.

[ahe, 2015/01/09 11:43:24]

Done in CL 837563004.

+          MessageKind.CANNOT_INSTANTIATE_TYPE_VARIABLE,
+          {'typeVariableName': name}, name, resolver.enclosingElement);
     } else if (!element.isClass && !element.isPrefix) {
       error(node, MessageKind.NOT_A_TYPE, {'node': name});
-      // TODO(ahe): Don't throw, recover from error.
-      throw new CompilerCancelledException(null);
+      element = new ErroneousElementX(

[Johnni Winther, 2015/01/09 08:44:18]

Ditto.

[ahe, 2015/01/09 11:43:24]

Done in CL 837563004.

+          MessageKind.NOT_A_TYPE, {'node': name}, name,
+          resolver.enclosingElement);
     }
     return element;
   }
 
   /// Assumed to be called by [resolveRedirectingFactory].
   Element visitRedirectingFactoryBody(RedirectingFactoryBody node) {
     Node constructorReference = node.constructorReference;
     return finishConstructorReference(visit(constructorReference),
         constructorReference, node);
   }
@@ skipping 62 matching lines @@
 }
 
 /// The result for the resolution of the `assert` method.
 class AssertResult implements ResolutionResult {
   const AssertResult();
 
   Element get element => null;
 
   String toString() => 'AssertResult()';
 }